Photos

From an email:

Observed a large crown in the hourglass while touring on Monday, April 14. The slide appeared to be a day or two old. We believe it was triggered by a cornice falling, looked like it broke 1-3 feet deep, and about 100 feet across. The slide went on almost a directly east facing aspect, and took out a large portion of the center of the chute. It slid through the choke, and down the apron, where in one place it stepped down to the ground level and exposed an area of rock about 20x20 ft. The debris ran the full path, well into the small saplings at the base of the chute. I wanted to get a picture and measure the depth of the debris, but temperatures were warming rapidly and I wasn't totally comfortable with the hangfire still near the crown.

Photo: J. Moss

Graupel is like hail. When buried it is a temporary weak layer but tends to bond fairly in a day or two. It tends to roll down hill and pool on aprons and cones. From April 3 north of Frazier Basin: "We felt like someone could have triggered fresh wind slabs in places, especially where the graupel had pooled to a dramatic degree.  Other than that the surface snow looked and felt pretty good." Photos: B. Fredlund

"The surface hoar grains were about .5-.8cm, and didn’t seem to be distributed too far down the slope into bear, maybe 2-300 vert max. The heat and solar from Tuesday broke it down lower in the valley. And it was pretty much gone on S facing aspects as we went back to the truck." Photo: L. Zukiewicz

A skier triggered an avalanche in the new snow on Sunday, March 31st.  This is a mid elevation slope near Woody Ridge south of Cooke City. Photo: B. Fredlund

Skiers got surprised when this slab pulled out yesterday.  No one was caught or injured.  New snow and some wind-loading created instability that luckiy did not step down to deeper layers. Photo: Anonymous

This small wind slab near Mt Backmore in the northern Gallain Range was human triggered. Althoug small, it's an obvious sign of instability. This type of slide would be far more hazardous in steep, high consequence terran. Photo D Nicolls 

This natural avalanche occurred on the north face of Mt Backmore. Heavy wind loading and weak facets near the ground was the recipe that caused this slide. The crown in the lookers left side of the photo is nearly seven feet deep. Avalanches of this nature will become more likely as more weight and stress is added to the snowpack. Photo B Bakken 

At least 7 avalanches were seen yesterday (3/26) on SW aspects in the Jones Creek area on the west side of the Bridger Range. All were several days old. Three of them stepped down into wet snow and created large debris piles. Photo: A. Whitmore

The circle shows my pit location on a south-facing slope.  We did not ski this slope because my stability tests were inconclusive on a layer of depth hoar found one foot off the ground. I do not trust this layer and try to avoid areas where thin, rockier terrain underlies the snowpack, which this slope has. Photo: GNFAC

This slide is a good example of slopes where avalanches can be triggered. Ones that are steeper than 35 degrees and have a relatively thin snowpack. Other parts of Skyline Ridge have areas of thin snow. Avalanches can be triggered in these zones but they will propagate into deeper areas and make a large avalanche. Photo: GNFAC

"Sun 3/16 we dug to the ground on a north aspect at ~ 8000 ft east of Emigrant peak and found 160cm of hard slab atop 20cm of very weak depth hoar.  Though probably too deep for meaningful test results, this layer collapsed completely when isolating a CT column and on 10 taps in an ECT." Photo: J. Martin

This recent natural avalanche was spotted yesterday (3/19) in the Northern Bridger Range on a SE aspect. Photo: B. Miller

This recent natural avalanche was spotted yesterday (3/19) in the Northern Bridger Range on a SE aspect. Photo: B. Miller

These deep slab avalanches up Flanders Creek in Hyalite were seen on Sunday, March 16. While not widespread, today's 28" of snow will tax these deep layers. Photo: C. Corey

The avalanche under Chimney Rock (north of Cooke City) was triggered by a sledder on Saturday, March 16. He was caught, pulled his airbag and not buried. This slope had hundreds of track on it throughout the winter.  Tracks do not indicate stability, especially when we are dealing with a deep slab avalanche problem. The untracked face of Crown Butte has a similar snowpack structure and would be a dangerous choice to play on. Photo: GNFAC

The crown was 3-4 feet deep.  The avalance was triggered aproximately 50 feet below the crown on a rock band.  Facets that formed in the early season fractured and propagated across the slope. Photo: GNFAC

Two snowmobilers triggered the south face of Abundance north of Cooke City on Saturday, March 16.  It was a deep slab avalanche that broke 3-4 feet deep and injured and partially buried one rider. Photo: GNFAC

This human triggered slide occurred near Daisy Pass north of Cooke City. The slide was triggered by a snowmobiler climbing the slope. The slide was triggered after the snowmobiler made the turn and was on his way down. He deployed his flotation device and was shot out the toe of the debris with his sled. Photo J. Kunzman